I am having a few issues on a 2009 Prius I just purchased. First I got the Yellow Check engine light, I went to a auto parts store and had them scan it. Code was P0101. Mass air flow or throttle body. They reset the computer with there device, right after I shut the car off and on to confirm the code was cleared. There was no check engine light. I turned it off went inside, came back out started the car and now I have the brake light on, tire pressure to low to read light, ABS light and VST light. Should I try and disconnecting the 12v battery and resetting the computer at this point ? If so how long does it need to be disconnected, to reset the computer?
Disconnecting the 12 V battery does not fix anything, it just deletes the codes. You might take a look at the MAF sensor, its connector, and wiring for corrosion or damage. With the MAF sensor removed, you could clean it and while the MAF sensor is removed you might as well clean the throttle plate and throttle body for good measure. Because you now have those other lights on, you might scan the car again and get the new codes.
You need clean MAF and check all connections. Air filter new etc. If brakes seem normal . Clear codes . Get a proper scanner. And see if brake codes and lites return.
These old cars that people sell can be a challenge. They often sell them because they give up on dealing with all the issues. I suggest you get the following items if you want to work on and get this car running, but you might want to accept that it will always need work, and is very complex. Many people on here have a lot of expertise and experience and knowledge but you have to be able to filter out the "opinions". It's a pretty steep learning curve. Get: digital voltmeter 12V bat charger HV bat charger (grid charger) techstream (and cheap laptop maybe) all these items are cheap to buy or build, take a little learning, but without them you are shooting in the dark. Good luck
Hello and welcome to PriusChat. Something that many people don't often consider when they go and buy something that is used - "why is someone selling this? Why does the owner not want it anymore?" Unfortunately sometimes it's because there's problems with it. Some of those problems can be quite pricey to repair. So, I don't know how DIY you are. You might consider getting a scantool to be able to read codes and data from the 14 to 16 computer systems on your Gen2 Prius. Here's a thread that reviews scantool apps and devices for a smartphone. Several can scan all systems on your car. https://priuschat.com/index.php?posts/3290690 You can also use the search feature to look info about Techstream, a laptop based diagnostic system used by Toyota dealers. Posted via the PriusChat mobile app.
